Process for breaking petroleum emulsions



Patented Jan. 27, 1953 UNITED STATES PATENT OFFICE PROCESS FOR BREAKING PETROLEUM EMULSIONS Melvin De Groote, University City, Mo., assignor to Petrolite Corporation, a corporation of Dela- No Drawing. Application December 1, 1950, Serial No. 198,752

Claims.

trolled conditions from mineral oil, such as crude oil and relatively soft waters or weak brines. Controlled emulsification and subsequent demulsification under the conditions just mentioned, are of significant value in removing impurities particularly inorganic salts from pipeline oil.

Demulsification as contemplated in the present application includes the preventive step of commingling the demulsifier with the aqueous component which would or might subsequently become either phase of the emulsion, in absence of such precautionary measure. Similarly, such demulsifier may be mixed with the hydrocarbon component.

The demulsifying agent employed in the present process is a fractional ester obtained from a polycarboxy acid and a sulfur-containing diol obtained by the oxypropylation of sulfur-containing compounds in which there are present two members selected from the class of OH and SH radicals, i. e., hydroxyl radicals and thio radicals in the sense that the alkyl mercaptans or similar compounds are also designated as alkane thiols. There is the further proviso that such sulfur-containing compound be free from any radical having 8 or more carbon atoms in a single uninterrupted group and the dihydroxylated compound prior to esterification must be water-insoluble and kerosene-soluble. Numerous sulfur-containing compounds susceptible to oxypropylation or, for that matter, to oxyethylation are well known. The one which I prefer to use is 2-mercaptoethanol, also the product known as thiodiethylene glycol, thiodiglycol, or di-2- hydroxyethyl sulfide. Just as satisfactory, of course, is the resultant compound obtained by treating 2-mercaptoethanol with one, two or three moles of ethylene oxide.

Other suitable compounds are obtained from mercaptans, or mercaptans which have been treated with ethylene oxide, propylene oxide, or

2 butylene oxide, followed by final treatment with glycide, the purpose of such final reaction being t convert a mono-reactive compound, 1. e., one having either only one hydroxyl or one thiol radical (SH radical) into a compound being di-' reactive, i. e., being able to combine with propylene oxide so as to yield diols as herein specified.

As an example of numerous other sulfur-containing compounds which are satisfactory for oxypropylation, attention is directed'to the fol-'- lowing:

OH(CH2) n.SS.(CHz) nOH where 11 may vary from 1 to 9 OH-CHQ-CH.CH2.ss-CH2-CH.OHLQH OH OH CH3. CHz.CHICH.CHz.SS. CHQ'CH.CHLOH2.CHB

H OH $112.CH1.SS.CHi-(iH-CHLCHLCHQ OH OH CH3. CH.CHg.SS. CH CH. CHg.OHz.CHz.CH3

CH: CH;

OH OH OH H where R is hydrogen or methyl I OH, s H1O H0 H. H6011 H, s H,

Compounds of the kind above enumerated, and numerous other suitable reactants, are described in U. S. Patents No. 1,570,262, 2,331,448, and 2,469,404, and German Patent No. 253,753.

Momentarily ignoring certain variants of structure which will be considered subsequently, the demulsifier may be exemplified by the following formula:

in which R is a divalent radical selected from (a) the class of radicals composed exclusively of carbon, hydrogen and sulfur, and (b) radicals composed exclusively of carbon, hydrogen, sulfur and oxygen, with the proviso that '(1) sulfur must be linked to at least one carbon atom in all such radicals and (2) such radicals must be free from any group having 8 or more uninterrupted carbon atoms; and n and n are whole numbers with the proviso that 12. plus 72 equals a sum varying from 15 to 80,; n" is a whole number not over 2, and R, is the radical of a polycarboxy acid in which n" has its previous significance, and with the further proviso that the parent dihydroxy compound prior to esterification be waterinsoluble and kerosene-soluble.

Attention is directed to the co-pending application of C. M. Blair, Jr., Serial No. 70,811, filed January 13, 1949 (now Patent 2,562,878, granted August 7, 1951), in which there is described, among other things, a process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of an esterification product of a dicarboxylic acid and a polyalkylene glycol in which the ratio of equivalents of polybasi'c acid to equivalents of polyalkylene glycol is in the range of 0.5 to 2.0, in which the alkylene group has from 2 to 3 carbon atoms, and in which the molecular weight of the product is between 1,500 to 4,000.

For convenience what is said hereinafter-will be divided into five parts:

Part 1 will be concerned with the oxypropylation of the specified sulfur-containing compound;

Part 2 will be concerned with the preparation of the esters from the oxypropylated compounds;

Part 3 will be concerned with the structure of the oxypropylated compounds obtained from the specified sulfur-containing initial materials;

Part 4 will be concerned with the use of the products herein described as demulsifiers for breaking water-in-oil emulsions, and

Part 5 will be concerned with certain derivatives which can be obtained from the diols of the aforementioned type. In some instances such derivatives are obtained by modest oxyethylation preceding the oxypropylation step, or oxypropylation followed by oxyethylation. This results in diols having somewhat different properties which can then be reacted with the same polycarboxy acids or anhydrides described in part 3 to give efiective demulsifying agents. For this reason a description of the apparatus makes casual mention of oxyethylation. For the same reason there is brief mention of the use of glycide.

PART 1 Previous reference has been made to a variety of sulfur-containing compounds, a large number of which have been illustrated. Attention is directed to the'fact that in a number of these compounds the linkage appears. In such instances the compounds were The compounds previously described and enumeratecl represent only a fraction of those which are well known, or can be prepared readily.

For a number of well known reasons equipment, whether laboratory size, semi-pilot plant size, pilot plant size, or large scale size, is not as a rule designed for a particular alkylene oxide. Invaniably and inevitably, however, or particularly in the case of laborator equipment and pilot plant size the design is such as to use any of the customarily available alkylene oxides, i. e., ethylene oxide, propylene oxide, butylene oxide, glycide, epichlorohydrin, styrene oxide, etc. In the subsequent description of the equipment it becomes obvious that it is adapted for oxyethyla-tion as well as oxypropylation.

Oxypropylations are conducted under a wide variety of conditions, not only in regard to presence or absence of catalyst, and the kind-of catalyst, but also in regard to the time of reaction, temperature of reaction, speed of reaction, pressure during reaction, etc. For instance, oxyalkylations can be conducted at temperatures up to approximately 200 C. with pressures in about the same range up to about 200 pounds per square inch. They can be conducted also at temperatures approximating the boiling point of water or slightly above, as for example to C. Under such circumstances the pressure will be less than 30 pounds per square inch unless some special procedure is employed as is sometime the case, to wit, keeping an atmosphere of inert gas such as nitrogen in the vessel during the reaction. Such low-temperature-low reaction rate oxypropylations have been described very completely in U. S. Patent No. 2,448,664, to H. R. Fife, et al., dated September 7, 1948. Low temperature, low pressure oxypropylations are particularly desirable where the compound being subjected to oxypropylatio-n contains one, two or three points of reaction only, such as monohydric alcohols, glycols and triols.

Although the word glycol or diol is usually applied to compounds containing carbon, hydrogen, and oxygen only, yet the sulfur-containing compounds herein are diols in the sense that they are dihydroxylated. Thus, the conditions which apply to the oxypropylation of certain glycols also apply in this instance.

Since low pressure-low temperature-low reaction speed oXypro-pylations require considerable time, for instance, 1 to 7 days of 24 hours each to complete the reaction they are conducted as a 'rule whether on a laboratory scale, pilot plant scale, or large scale, so as to operate automatically. The prior figure of seven days applies especially to large-scale operations. I have used conventional equipment with two added automatic features; (a) a solenoid controlled valve which shuts off the propylene oxide in event that the temperature gets outside a predetermined and set range, for instance, 95 to 120 C., and (b) another solenoid valve which shuts off the propylene oxide (or for that matter ethylene oxide if it is being used) if the pressure gets beyond a predetermined range, such as 25 to 35 pounds. Otherwise, the equipment is substantially the same as is commonly employed for this purpose where the pressure of reaction is higher, speed of reaction is higher, and time of reaction is much shorter. In such instances such automatic controls are not necessarily used.

Thus, in preparing the various examples I have found it particularly advantageous to use laboratory equipment or pilot plant which is designed to permit continuous oxyalkylation whether it be oxypropylation or oxyethylati-on. With certain obvious changes the equipment can be used also to permit oxyalkylation involving the use of glycide where no pressure is involved except the vapor pressure of a solvent, if any, which may have been used as a diluent.

As previously point-ed out the method of using propylene oxide is the same as ethylene oxide. This point is emphasized only for the reason that the apparatus is so designed and constructed as to use either oxide.

The oxypropylation procedure employed in the preparation of the oxy-alkylated derivatives has been uniformly the same, particularly in light of the fact that a continuous automatically-controlled procedure was employed. In this procedure the autoclave was a conventional autoclave made of stainless steel and having a capacity of approximately gallons and a working pressure of one thousand pounds gauge pressure. This pressure obviously is far beyond any requirement as far as propylene oxide goes unless there is a reaction of explosive violence involved due to accident. The autoclave was equipped with the conventional devices and openings, such as the variable-speed stirrer operating at speeds from 50 R. P. M. to 500 R. P. M.; thermometer well and thermocouple for mechanical thermometer; emptying outlet; pressure gauge, manual vent line; charge hole for initial reactants; at least one connection for introducing the alkylene oxide, such as propylene oxide or ethylene oxide, to the bottom of the autoclave; along with suitable devices for both cooling and heating the autoclave, such as a cooling jacket, and, preferably, coils in addition thereto, with the jacket so arranged that it is suitable for heating with steam or cooling with water and further equipped with electrical heating devices. Such autoclaves are, ofcourse, in essence small-scale replicas of the usual conventional autoclave used in oxyalky-lation procedures. In some instances in exploratory preparations an autoclave having a smaller capacity, for instance, approximately 3 /2 liters in one case and about 1% gallons in another case, was used.

Continuous operation, or substantially continuous operation, was achieved by the use of a separate container to hold the alkylene oxide being employed, particularly propylene oxide. In conjunction with the smaller autoclaves, the container consists essentially of a laboratory bomb having a capacity of about one-half gallon, in somewhat in excess thereof. In some instances a larger bomb was used, to wit, one having a capacity of about one gallon. This bomb was equipped, also, with an inlet for charging, and an eductor tube going to the bottom of the container so as to permit discharging of alkylene oxide in the liquid phase to the autoclave. A bomb having a capacity of about 60 pounds was used in connection with the 15-gallon autoclave. Other conventional equipment consists, of course, of the rupture disc, pressure gauge, sight feed glass, thermometer, connection for nitrogen for pressuring bomb, etc. The bomb was placed on a scale during use. The connection between the bomb and the autoclave were flexible stainless steel hose or tubing so that continuous weighings could be made without breaking or making any connections. This applies also to the nitrogen line, which was used to pressure the bomb reservoir. To the extent that it was required, any other usual conventional procedure or addition which provided greater safety was used, of course, such as safety glass protective screens, etc.

Attention is directed again to what has been said previously in regard to automatic controls which shut off the propylene oxide in event temperature of reaction passes out of the predetermined range or if pressure in the autoclave passes out of predetermined range.

With this particular arrangement practically all oxypropylations become uniform in that the reaction temperature was held within a few degrees of any selected point, for instance, if C. was selected as the operating temperature the maximum point would be at the most C. or 112 0., and the lower point would be 95 or possibly 98 C. Similarly, the pressure was held at approximately 30 pounds within a 5-pound variation one way or the other, but might drop to practically zero, especially where no solvent such as xylene is employed. The speed of reaction was comparatively slow under such conditions as compared with oxyalkylations at 200 C. Numerous reactions were conducted in which the time varied from one day (24 hours) up to three days (7 2 hours), for completion of the final member of a series. In some instances the reaction may take place in considerably less time, i. e., 24 hours or less, as far as a partial oxypropylation is concerned. The minimum time recorded was about a 3-hour period in a single step. Reactions indicated as being complete in 10 hours may have been complete in a lesser period of time in light of the automatic equipment employed. This applies also where the reactions were complete in a shorter period of time, for instance, 4 to 5 hours. In the addition of propylene oxide, in the autoclave equipment as far as possible the valves were set so all the propylene oxide if fed continuously would be added at a rate so that the predetermined amount would react within the first 15 hours of the 24-hour period or two-thirds of any shorter period. This meant that if the reaction was interrupted automatically for a period of time for pressure to drop or temperature to drop the predetermined amount of oxide would still be added in most instances well within the predetermined time period. Sometimes Where the addition was a comparatively small amount in a 10-hour period there would be an unquestionable speedin up of the reaction, by simply repeating the examples and using 3, 4, or 5 hours instead of 10 hours.

When operating at a comparatively high temperature, for instance, between 150 to 200 6., an unreacted alkylene oxide such as propylene oxide, makes its presence felt in the increase in pressure or the consistency of a higher pressure. However, at a low enough temperature it may happen that the propylene oxide goes in as a liquid. If so, and if it remains unreacted there is, of course, an inherent danger and appropriate steps must be taken to safeguard against this possibility; if need be a sample must be withdrawn and examined for unreacted propylene oxide. One obvious procedure, of course, is to oxypropylate at a modestly higher temperature, for instance, at 140 to 150 C. Unreacted oxide affects determination of the acetyl or hydroxyl value of the hydroxylated compound obtained.

The higher the molecular weight of the compound, i. e., towards the latter stages of reaction, the longer the time required to add a given amount of oxide. One possible explanation is that the molecule, being larger, the opportunity for random reaction is decreased. Inversely, the lower the molecular weight the faster the reaction takes place. For this reason, sometimes at least, increasing the concentration of the catalyst does not appreciably speed up the reaction, particularly when the product subjected to oxyalkylation has a comparatively high molecular weight. However, as has been pointed out previously, operating at a low pressure and a low temperature even in large scale operations as much as a week or ten days time may lapse to obtain some of the higher molecular weight derivatives from monohydric or dihydric materials.

In a number of operations the counterbalance scale or dial scale holding the propylene oxide bomb was so set that when the predetermined amount of propylene oxide had passed into the reaction the scale movement through a time operating device was set for either one to two hours so that reaction continued for 1 to 3 hours after the final addition of the last propylene oxide and thereafter the operation was shut down. This particular device is particularly suitable for use on larger equipment than laboratory size autoclaves, to wit, on semi-pilot plant or pilot plant size, as well as on large scale size. This final stirring period is intended to avoid the presence of unreacted oxide.

In this sort of operation, of course, the temperature range was controlled automatically by either use of cooling water, steam, or electrical heat, so as to raise or lower the temperature. The pressuring of the propylene oxide into the reaction vessel was also automatic insofar that the feed stream was set for a slow continuous run which was shut off in case the pressure passed a predetermined point as previously set out. All the points of design, construction, etc., were conventional including the gauges, check valves and entire equipment. As far as I am aware at least two firms, and possibly three, specialize in autoclave equipment such as I have employed in the laboratory, and are prepared to furnish equipment of this same kind. Similarly pilot plant equipment is available. This point is simply made as a precaution in the direction of safety. Oxyalkylations, particularly involving ethylene oxide, glycide, propylene oxide, etc., should not be conducted except in equipment specifically designed for the purpose.

Example 1a The starting material was a commercial grade of 2-mercaptoethanol. The particular autoclave employed was one with a capacity of 15 gallons or on the average of pounds of reaction mass. The speed of the stirrer could be varied from to 350 R. P. M. 9.5 pounds of 2-mercaptoethano1 were charged into the autoclave along with one pound of caustic soda. The reaction pot was flushed out with nitrogen. The autoclave was sealed and the automatic devices adjusted for injecting a total of slightly over 87 pounds of propylene oxide in approximately 3 hours. The pressure regulator was set for a maximum of 35 to 37 pounds per square inch. This meant that the bulk of the reaction could take place and probably did take place at a lower pressure. This comparatively low pressure was the result of the fact that considerable catalyst was present. The propylene oxide was added comparatively slowly and, more important, the selected temperature range was 220 to 225 F. (just slightly above the boiling point of water). The initial introduction of propylene oxide was not started until the heating devices had raised the temperature to about the boiling point of water At the completion of the reaction a sample was taken and oxypropylation proceeded as in Example 2a, immediately succeeding.

Ewample 211.

66.5 pounds of the reaction mass identified as Example la, preceding, were permitted to remain in the reaction vessel and without the addition of any more catalyst 43 pounds of propylene oxide were added. The oxypropylation was conducted in substantially the same manner with regard to pressure and temperature as in Example la, preceding, except that the reaction was complete in slightly less time, that is, 3 hours instead of 3%; hours. At the end of the reaction period part of the sample was withdrawn and oxypropylation continued as described in Example 3a, following.

Erampie 3:1

62.15 pounds of the reaction mass identified as Example 2a, preceding, were permitted to remain in the reaction vessel. 43 pounds of propylene oxide were introduced in the third stage. No ad ditional catalyst was added. The time period required was the same as in the preceding example, i. e., 3 hours. The conditions of reaction as far as temperature and pressure were concerned were substantially the same as in Example 1a, preceding. At the completion of the reaction part of the reaction mass was withdrawn and the remainder subjected to oxypropylation as described in Example 411, following.

Example 4a 61.2 pounds of the reaction mass identified as Example 3a, preceding, were permitted to remain in the autoclave. Without adding any more catalyst this Was subjected to further oxypropyla tion as in the preceding example. The amount of propylene oxide added was 43.38 pounds. This was introduced in a 4-hour period. The conditions in regard to temperature and pressure were substantially the same as in Example 1a, preceding. At the end of the reaction period part of the reaction mass was Withdrawn and the remainder was subjected to further oxypropylation as described in Example 5a, following,

Example 5a Approximately 68.9 pounds of the reaction mass were permitted to stay in the autoclave. No additional catalyst was introduced. 27.5 poundsof j propylene oxide were added. The time required to add this propylene oxide was 2 hours. The conditions of reaction in regard to temperature andpressure were substantially the same as in.

theexamples appearing in the patent previously mentioned. I I

PART 2 I H As previously pointed out the present invention is concerned with acidic esters obtained from the Example precedmg' oxypropylated derivatives described in Part 1, Example 6a immediately preceding, and polycarboxy acids,

. particularly dicarboxy acids such as adipic acid,

Approximately 88.65 pounds of reaction masS- phthalic acid, or anhydride, succinic acid, diglywere permitted to stay in the autoclave. No ad- 10 collic acid, sebacic acid, azelaic acid, aconitic acid, t o a cat lys was introduced. 2 pou ds o maleic acid or ahhydride, citraconic acid or anpropylene oxide were added. The time require hydride, maleic acid or anhydride adducts as obto add this propylene Oxide WaS 3% hours. Thetained by the Dials-Alder reaction from products conditions of reaction in regard to t p such asmaleic anhydride, and cyclopentadiene. and pressure were substantially the same as in- Such acids should be heat stable so they are not Example la, preceding. decomposed during esterification. They may con- .What is said herein is presented in tabular tain as many as 36 carbon atoms as, for example, form in Table I immediately following, with some the acids obtained by dimerization of unsaturated added information as to molecular weight and fatty acids, unsaturated monocarboxy fatty. acids, as to solubility of the reaction product in water, or unsaturated monocarboxy acids having- 18 carxylene, and kerosene. bon atoms. Reference to-the acid in the hereto TABLE 1 Composition Before Composition at End M Max by Max. Pres, Tim 1 3i i ia gxide (llati- 1112c? 3 21 gi rlide (llastta- 52$; T???" 5 Hrs? it? its?" iii. wi. ad?" its." its. 59-111 15.. 9.5 1.0 1,240 9.5 87. 1.0 820 220-225 35-37 3 2a 5. 45 59.12 .53 2,055 5. 45 102.12 .02 1, 213 220-225 35-37 3 35. 3.55 53.10 .39 3,490 3. 00 101.10 .39 1,920 220-225 35-37 3 4a 2.13 52. 92 .23 5, 930 2.13 102. .23 3,300 220-225 -37 4 5a-.- 1.40 07. 35 .15 8,390 1. 94. 25 .15 2,900 220-225 35-37 2 5. 6a 1.29 37. 22 .14 10, 470 1. 29 109.22 .14 3,040 220-225 35-37 3 In the above examples, la was emulsifiable in appended claims obviously includes the anhywater, soluble in xylene, and dispersible in kerodrides or any other obvious equivalents. My prefsene. The solubility of Examples 2a through fia, erence, however, is to use polycarboxy acids havinclusive, was identical in that they were all 40 ing not over8carbon atoms. water-insoluble, all xylene-soluble, and all kero- The production of esters including acid esters sene-soluble. (fractional esters) from polycarboxy acidsand The products so obtained are liquids showing glycols or other hydroxylated compounds is well modest viscosity and perhaps a slight odor. In known. Needless to say, various'compounds may each instance there was some residual basicity be used such as the low molal ester, the anhydue to the catalyst which, of course, would be true also if sodium methylate had been employed. Speaking of insolubility in water or solubility in kerosene such solubility test can be made simply by shaking small amounts of the materials in a test tube with water, for instance, using 1% to 5% approximately based on the amount of water present.

. Needless to say, there is no complete conversion of propylene oxide into the desired hydro-xylated compounds. This is indicated by the :fact that the theoretical molecular weight based on a statistical average is greater than the molecular weight calculated by usual methods on basis of acetyl or hydroxyl value. Actually, there is no completely satisfactory method for determining molecular weights of these types of compounds with a high degree of accuracy when the molecular weights exceed 2,000. In some instances the acetyl value or hydroxyl value serves as satisfactorily an index to the molecular weight as any other procedure, subject to the above limitations, and especially in the higher molecular weight range. If any difiiculty is encountered in the manufacture of the esters as described in Part 2 the stoichiometrical amount of acid or acid compound should be taken which corresponds to the indicated acetyl or hydroxyl value. This matter has been discussed in the literature and is a matter of common knowledge and requires no further elaboration. In fact, it is illustrated by some of dride, the acyl chloride, etc. However, for purpose of economy it is customary to use either the acid or the anhydride. A conventional procedure is employed. On a laboratory scale one can employ a resin pot of the kind described in U. S. Patent No. 2,499,370, dated March '7, 1950 to De Groote and Keiser, and particularly with one more opening 'to permit the use of a porous spreader if hydrochloric acid gas is to be used as a catalyst. Such device or absorption spreader consists of minute alundum thimbles which are connected to a glass'tube. One can add a sulfonic acid such as'para-toluene sulfonic acid as a catalyst. There is some objection to this because in some instances there'is some evidence that this acid catalyst tends to decompose or rearrange the oxypropylated compounds, and particularly likely to do so if the esterification temperature is too high. In the case of polycarboxy acids such as diglycollic acid, which is strongly acidic there is no need to add any catalyst. The use of hydrochloric gas has one advantage over paratoluene sulfonic acid and that is that at the end of the reaction it can be removed by flushing out with nitrogen, whereas there is no reasonably convenient means available of removing the paratoluene sulfonic acid or other sulfonic acid employed. If hydrochloric acid is employed one need only pass the gas through at an exceedingly slow rate so as to keep the reaction mass acidic. Only a'trace of acid need be-present. I

have employed hydrochloric acid gas or theaqueous acid itself to eliminate the initial basic material. My preference, however, is to use no catalyst whatsoever and to insure complete dryness of the diol as described in the final procedure just preceding Table 2.

The products obtained in Part 1 preceding may contain a basic catalyst. As a general procedure I have added an amount of half-concentrated hydrochloric acid considerably in excess of what is required to neutralize the residual catalyst. The mixture is shaken thoroughly and allowed to stand overnight. It is then filtered and refluxed with the xylene present until the water can be separated in a phase-separating trap. As soon as the product is substantially free from water the distillation stops. This preliminary step can be carried out in the flask to be used for esterification. If there is any further deposition of sodium chloride during the reflux stage needless to say a second filtration may be required. In any event the neutral or slightly acidic solution of the oxypropylated derivatives described in Part 1 is then diluted further with sufficient xylene, decalin, petroleum solvent, or the like, so that one has obtained approximately a 45% solution. To this solution there is added a polycarboxylated reactant as previously described, such as phthalic anhydride, succinic acid or anhydride, diglycollic acid, etc. The mixture is refluxed until. esterification is complete as indicated by elimination of water or drop in carboxyl value. Needless to say, if one produces a half-ester from an anhydride such as phthalic anhydride, no Water is eliminated. However, if it is obtained from diglycollic acid, for example, water is eliminated. All such procedures are conventional and have been so thoroughly described in the literature that further consideration will be limited to a few examples and a comprehensive table.

Other procedures for eliminating the basic residual catalyst, if any, can be employed. For example, the oxyalkylation can be conducted in absence of a solvent or the solvent removed after oxypropylation. Such oxypropylation end product can then be acidified with just enough concentrated hydrochloric acid to just neutralize the residual basic catalyst. To this product one can then add a, small amount of anhydrous sodium sulfate (sufiicient in quantity to take up any water that is present) and then subject the mass to centrifugal force so as to eliminate the sodium sulfate and probably the sodium chloride formed. The clear somewhat viscous straw-colored amber liquid so obtained may contain a small amount of sodium sulfate or sodium chloride but, in any event, is perfectly acceptable for esterification in the manner described.

It is to be pointed out that the products here described are not polyesters in the sense that there is a plurality of both diol radicals and acid radicals; the product is characterized by having only one diol radical.

In some instances and, in fact, in many instances I have found that in spite of the dehydration methods employed above that a mere trace of water still comes through and that this mere trace of water certainly interferes with the acetyl or hydroxyl value determination, at least when a number of conventional procedures are used and may retard esterification, particularly where there is no sulfonic acid or hydrochloric acid present as a catalyst. Therefore, I have referred to use the following procedure: I have employed about 200 grams of the diol as described in Part 1, preceding; I have added about 60 grams of benzene, and then refluxed this mixture in the glass resin pot using a phase-separating trap until the benzene carried out all the water present as water of solution or the equivalent. Ordinarily this refluxing temperature is apt to be in the neighborhood of 130 to possibly 150 C. When all this water or moisture has been removed I also withdraw approximately 20 grams or a little less benzene and then add the required amount of the carboxy reactant and also about 15 0 grams of a high boiling aromatic petroleum solvent. These solvents are sold by various oil refineries and, as far as solvent effect act as; if they were almost completely aromatic in character. Typical distillation data in the particular type I have employed and found very satisfactory are: the following:

I. B. P., 142 C. ml., 242 C. 5 ml., 200 C. ml., 244 C. 10 ml., 209 C. ml., 248 C. 15 1111., 215 C. ml., 252 C. 20 ml., 216 C. 1111., 252 C. 25 m1., 220 C. ml., 260 C. 30 ml., 225 C. ml., 264 C. 35 ml., 230 C. ml., 270 C. 40 ml., 234 C. m1., 280 C. 45 ml., 237 C. ml., 307 C.

After this material is added, refluxing is continued, and, of course, is at a high temperature, to wit, about to C. If the carboxy reactant is an anhydride needless to say no water of reaction appears; if the carboxy reactant is an acid water of reaction should appear and should be eliminated at the above reaction temperature. If it is not eliminated I simply separate out another 10 to 20 cc. of benzene by means of the phase-separating trap and thus raise the temperature to or C, or even to 200 0., if need be. My preference is not to go above 200 C.

The use of such solvent is extremely satisfactory provided one does not attempt to remove the solvent subsequently except by vacuum distillation and provided there is no objection to a little residue. Actually, when these materials are used for a purpose such as demulsification the solvent might just as Well be allowed to remain. If the solvent is to be removed by distillation, and particularly vacuum distillation, then the high boilmg aromatic petroleum solvent might well be replaced by some more expensive solvent, such as decalin or an alkylated decalin which has a rather definite or close range boiling point. The removal of the solvent, of course, is purely a conventional procedure and requires no elaboration.

In the appended table solvent #7-3, which appears in all instances, is a mixture of 7 volumes of the aromatic petroleum solvent previously described and 3 volumes of benzene. This was used, or a similar mixture, in the manner previously described. In a large number of similar examples decalin has been used but it is my preference to use the above mentioned mixture and particularly with the preliminary step of removing all the water. If one does not intend to remove the solvent my preference is to use the petroleum solvent-benzene mixture although obviously any of the other mixtures, such as decalin and xylene, can be employed.

The data included in the subsequent tables, 1. e., Tables 2 and 3, are self-explanatory, and

is not a factor and decolorization is not justified.

In the above instances I have permitted the solvents to remain present in the final reaction mass. In other instances I have followed the same procedure using decalin or a mixture of decalin or benzene in the same manner and ultimately removed all the solvents by vacuum distillation. Appearances of the final products are much the same as the diol before esterification and in some instances were somewhat darker in color and had a more reddish cast and perhaps were somewhat more viscous.

PART 3 Previous reference has been made to the fact that diols (sulfur-free compound) such as polypropylene glycol of approximately 2,000 molecular weight, for example, have been esterified with dicar-boxy acids and employed as demulsifying agents. The herein described compounds are different from such diols although both, it is true, are high molecular weight dihydroxylated compounds. The instant compounds have present a sulfur radical which in some manner or other effects both the structure and the orientation of the molecule at an interface. Sulfur in some ways is somewhat comparable to the element oxygen, although this is only a partial analogy. Regardless of what the difference may be the fact still remains that the compounds of the kind herein described maybe, and frequently are, or better on a quantitative basis than the simpler compound previously described, and demulsify faster and give cleaner oil in many instances. The method of making such comparative tests has been described in a booklet entitled Treating Oil Field Emulsions, used in the Vocational Training Course, Petroleum Industry Series, of the American Petroleum Institute.

It may be well to emphasize also the fact that oxypropylation does not produce a single compound but a cogeneric mixture. The factor involved is the same as appears if one were oxypropylating a monohydric alcohol or a glycol. Momentarily, one may consider the structure of a polypropylene glycol, such as polypropylene glycol of 2000 molecular weight. Propylene glycol has a primary alcohol radical and a secondary alcohol radical. In this sense the building unit which forms polypropylene glycols is not sym metrical. Obviously, then, polypropylene glycols can be obtained, at least theoretically, in which two secondary alcohol groups are united or a secondary alcohol group is united to a primary alcohol group, etherization being involved, of course, in each instance.

Usually no effort is made to diiferentiate between oxypropylation taking place, for example, at the primary alcohol unit radical or the secondary alcohol radical. Actually, when such products are obtained, such as a high molal polypropylene glycol or the products obtained in the manner herein described one does not. obtain a single derivative such as I-IO(RO) 12H in which n has one and only one value, for instance, 14, 15 or 16, or the like. Rather, one obtains a cogeneric mixture of closely related or touching homologues. These materials invariably have high molecular weights and cannot be separated from one another by any known procedure without decomposition. The properties of such mixture represent the contribution of the various individual members of the mixture. On a statistical basis, of course, 11. can be appropriately specified. For practical purposes one need only consider the oxypropylation of a monohydric alcohol because in essence this is substantially the mechanism involved. Even in such instances where one is concerned with a monohydric reactant one cannot draw a single formula and say that by following such procedure one can readily obtain or or of such compound. However, in the case of at least monohydric initial reactants one can readily draw the formulas of a large number of compounds which appear in some of the probable mixtures or can be prepared as components and mixtures which are manufactured conventionally.

Simply by way of illustration reference is made to the copending application of De Groote, Wirtel, and Pettingill, Serial No. 109,791, filed August 11, 1949 (now Patent 2,549,434, granted April 17, 1951).

However, momentarily referring again to a monohydric initial reactant it is obvious that if one selects any such simple hydroxylated compound and subjects such compound to oxyalkylation, such as oxyethylation, or oxypropylation, it becomes obvious that one is really producing a polymer of the alkylene oxides except for the terminal group. This is particularly true where the amount of oxide added is comparatively large, for instance, 10, 20, 30, 40, or 50 units. If such compound is subjected to oxye-thylation so as to introduce 30 units of ethylene oxide, it is well known that one does not obtain a single constituent which, for the sake of convenience, may be indicated as RO(C2H40)30H. Instead, one obtains a cogeneric mixture of closely related homologues, in which the formula may be shown as the following, RO(C2H4O)1LI'I, wherein n, as far as the statistical average goes, is 30, but the individual members present in significant amount may vary from instances where n has a value of 25, and perhaps less, to a point Where n may represent 35 or more. Such mixture is, as stated, a cogeneric closely related series of touching homologous compounds. Considerable investigation has been made in regard to the distribution curves for linear polymers. Attention is directed to the article entitled Fundamental principles of condensation polymerization, by Flory, which appeared in Chemical Reviews, Volume 39, No. 1, page 137.

In the instant case one may start with compounds where the terminal groups are exclustively the SH radical. A radical can be treated first with ethylene oxide and then with propylene oxide, or with propylene oxide directly. As far as what has been Said immediately preceding or elsewhere one need not difierentiate between the SH radical and the OH radical as far as oogeneric mixtures obtained by oxypropylation are concerned.

Unfortunately, as has been pointed out by Flory and other investigators, there is no satisfactory method, based on either experimental or mathematical examination, of indicating the exact proportion of the various members of touching homologous series which appear in cogeneric condensation products of the kind described. This means that from the practical standpoint, i. e., the ability to describe how to make the product under consideration and how to repeat such production time after time without difiiculty, it is necessary to resort to some other method of description, or else consider the value of n, in formulas such as those which have appeared previously and which appear in the claims, as representing both individual constituents in which n has a single definite value, and also with the understanding that n represents the average statistical value based on the assumption of completeness of reaction.

This may be illustrated as follows: Assume that in any particular example the molal ratio of the propylene oxide to 2-mercaptoethanol or other selected sulfur compounds as specified is 30 to 1. Actually, one obtain products in which n probably varies from 10 to 20, perhaps even further. The average value, however, is 15, assuming, as previously stated, that the reaction is complete. The product described by the formula is best described also in terms of method of manufacture.

PART 4 Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent, such as water, petroleum hydrocarbons, such as benzene, toluene, xylene, tar acid oil, cresol, anthracene oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc., may be employed as diluents. Miscellaneous solvents such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained in the refining if petroleum, etc., may be employed as diluents. Similarly, the material or materials employed as the demulsifyin agent of my process may be admixed with one or more of the solvents customarily used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone or in admixture with other suitable wellknown classes of demulsifying agents.

It is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oiland water-solubility. Sometimes they 4 may be used in a form which exhibits relatively limited oil-solubility. However, since such reagents are frequently used in a ratio of 1 to 10,000 or 1 to 20,000, or 1 to 30,000, or even 1 to 40,000, or 1 to 50,000 as in desalting practice, such an apparent insolubility in oil and water is not significant because said reagents undoubtedly have solubility within such concentrations. This same fact is true in regard to the material or materials employed as the demulsifying agent of my process.

In practicing my process for resolving petroleum emulsions of the water-in-oil type, a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedure being used alone or in combination with other demulsifying procedure, such as the electrical dehydration process.

One type of procedure is to accumulate a volume of emulsified oil in a tank and conduct a batch treatment type of demulsification procedure to recover clean oil. In this procedure the emulsion is admixed with the demulsifier, for example by agitating the tank of emulsion and slowly dripping demulsifier into the emulsion. In some cases mixing is achieved by heating the emulsion while dripping in the demulsifier, depending upon the convection currents in the emulsion to produce satisfactory admixture. In a third modification of this type of treatment, a circulating pump withdraws emulsion from, c. g.,

the bottom of the tank, and reintroduces it into the top of the tank, the demulsifier being added, for example, at the suction side of said circulating pump.

5 In a second type of treating procedure, the demulsifier is introduced into the well fluids at the Well-head or at some point between the wellhead and the final oil storage tank, by means of an adjustable proportioning mechanism or proportioning pump. Ordinarily the flow of fluids through the subsequent lines and fittings sufiices to produce the desired degree of mixing of demulsifier and emulsion, although in some instances additional mixing devices may be introduced into the flow system. In this general procedure, the system may include various mechanical devices for withdrawing free water, separating entrained water, or accomplishing quiescent settling of the chemicalized emulsion. Heating devices may likewise be incorporated in any of the treating procedures described herein.

A third type of application (down-the-hole) of demulsifier to emulsion is to introduce the demulsifier either periodically or continuously in diluted or undiluted form into the well and to allow it to come to the surface with the well fluids, and then to flow the chemicalized emulsion through any desirable surface equipment, such as employed in the other treating procedures.

This particular type of application is decidedly useful when the demulsifier is used in connection with acidification of calcareous oil-bearing strata, especially if suspended in or dissolved in the acid employed for acidification.

In all cases, it will be apparent from the foregoing description, the broad process consists simply in introducing a relatively small proportion of demulsifier into a relatively large proportion of emulsion, admixing the chemical and 0 emulsion either through natural flow or through special apparatus, with or without the application of heat, and allowing the mixture to stand quiescent until the undesirable water content of the emulsion separates and settles from the mass.

The following is a typical installation.

A reservoir to hold the demulsifier of the kind described (diluted or undiluted) is placed at the well-head where the eflluent liquids leave the well. This reservoir or container, which may vary from 5 gallons to 50 gallons for convenience,

is connected to a proportioning pump which injects the demulsifier drop-wise into the fluids leaving the well. Such chemicalized fluids pass through the flowline into a settling tank. The

settling tank consists of a tank of any convenient size, for instance, one which will hold amounts of fluid produced in 4 to 24 hours (500 barrels to 2000 barrels capacity), and in which there is a perpendicular conduit from the top of the tank 69 to almost the very bottom so as to permit the incoming fluids to pass from the top of the settling tank to the bottom, so that such incoming fluids do not disturb Stratification which takes place during the course of demulsification. The settling tank has two outlets, one being below the water level to drain off the water resulting from demulsiflcation or accompanying the emulsion as free water, the other being an oil outlet at the top topermit the passage of dehydrated oil to a 0 second tank, being a storage tank, which holds pipeline or dehydrated oil. If desired, the conduit or pipe which serves to carry the fluids from the well to the settling tank may include a section of pipe with bafiles to serve as a mixer, to insure thorough distribution of the demulsifier through- 19 out the fluids, or a heater for raising the temperature of the fluids to some convenient tern,- perature, for instance, 120 to 160 F., or both heater and mixer.

Demulsification procedure is started by simply setting the pump so as to feed a comparatively large ratio of demulsifier, for instance, 1:5,000. As soon as a complete break" or satisfactory demulsification is obtained, the pump is regulated until experience shows that the amount of demulsifier being added is just sufficient to produce clean or dehydrated oil. The amount being fed at such stage is usually 110,000, 115,000, 1:20,- 000, or the like.

In many instances the oxyalkylated products herein specified as .demulsifiers can be conveniently used without dilution. However, as previously noted, they may be diluted as desired with any suitable solvent. For instance, by mixing 75 parts by weight of the product of Example 11?) with 15 parts by weight of xylene and 10 parts by weight of isopropyl alcohol, an excellent demulsi- .fier isobtained. Selection of the solvent will vary, depending .upon the solubility characterise tics of the oxyalkylated product, and of course will be dictated in part by economic considera.- .tions, i. e., cost.

As noted above, the products herein described may be used not only in diluted form, but also may be used admixed with some other chemical .clem-ulsifier.

PART Previous reference has been made to exyalkylating agents other than propylene oxide, such as ethylene oxide. Obviously variants can be prepared which do not depart from what is said herein but do produce modifications. Z-mercaptoethanol or other suitable sulfur-containing compound as specified herein, can be reacted with ethylene oxide in modest amounts and then subjected to oxypropylation provided that the resultant derivative is (a) Water-insoluble, b)' kerosene-soluble, and (c) has present 15 to 180 alkylene .oxide radicals. Needless to say, in order to have water-insolubility and kerosenesolubility the large majority must'be propylene oxide. Other variants suggest themselves as, for example, replacing propylene oxide by 'butyleneoxide.

More specifically, one mole of 2-mercaptoethanol can be treated with 2, 4 or 6 moles of ethylene oxide and then treated with propylene oxide so as to produce a water-insoluble, kerosene-soluble oxyalkylated product in which there are present 15 to 80 oxide radicals as previously specified. Similarly the propylene oxide can be added first and then the ethylene oxide, or random oxyalkylation can be employed using a mixture of the two oxides. The compounds so obtained ,are' readily esterified in the same manner as described in Part 2, preceding. incidentally, the diols described in Part -1 or the modifications described therein can be treated with various reactants such as glycide, epichlorohydrin, dimethyl sulfate, sulfuric acid,'maleic anhydride, ethylene imine, etc. If treated with epichlorohydrin or monochloroacetic acid the resultant product can be further reacted with a tertiary amine such as pyridine, or the like, to give quaternary ammonium compounds. If treated with maleic anhydride to give a total ester the resultant can be treated .with sodium bisulfite to yield a sulfosuccinate. Sulfo groups can be introduced also by means of a sulfating a ent as previously suggested, or by treating the 20- c hloroac etic acid resultant with sodium sulfite.

I have found that if such hydroxylated com-.- pound or compounds are reacted further so as to produce entirely new derivatives, such new derivatives have the properties of the original hydroxylated compound insofar that they are effective and valuable demulsifying agents for resolution of water-inoil emulsions as found in the petroleum industry, as break inducers in doctor treatment of sour crude, etc.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is:

l. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsiner including hydrophile synthetic products; said hydrophile synthetic products being characterized by the following formula:

0 o .(HOOl )n"R (0HGC3)nR'+( C3HtQ)n'R( CO0H)n" in which E is a divalent radical selected from (a) the class of radicals composed exclusively of carbon, hydrogen and sulfur, and (b) radicals composed exclusively of carbon, hydrogen, ulfur and oxygen, with the proviso that (1) sulfur must be linked to at least one carbon atom in all such radicals andis linked only to atoms of the roup consisting of carbon and sulfur, and (2) such radicals must be free from any group having 8 or more uninterrupted carbon atoms; and n and n are whole numbers wit the proviso that 11. plus 1?. equals a sum varying from 15 to n" is a whole number not over 2, and

R is the radical of a polycarboxy acid coon: R

\(COOH)1\" in which n" has its previous significance, and with the further proviso that the parent dihydroxy compound prior to esterification be waterinsoluble and kerosene-soluble.

2. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsiner including hydrophile synthetic products; said hydrophile synthetic products being char,- acterized by the following formuls:

o (HOOC),wR J(0HuCa)nRr(CaHoO)n' R(C0 0H)n'! in which R is a divalent radical selected from (a) the class of radicals composed exclusively of carbon, hydrogen and sulfur, and (b) radicals composed exclusively of carbon, hydrogen, sulfur and oxyg n, with the proviso that (l) sulfur must be linked to at least one carbon atomin all such radicals and is linked only to atoms of thegroup consisting of carbon and sulfur, and (2) such radicals must be free from any group having 8 or more uninterrupted carbon atoms; and of and n are whole numbers with the proviso that n plus n equals a sum varying from 15 to 80 n is a whole number not over 2, and R is the radical of a polycarboxy acid CO H m a in h h n" h s ie s g ficance; said polycarboxy acid havingnot more than 8 carbon atoms; and with the further proviso that. the pa e t d hydroxy compo n prior to acrifiin which R is a divalent radical selected from (a) the class of radicals composed exclusively of carbon, hydrogen and sulfur, and (b) radicals composed exclusively of carbon, hydrogen, sulfur and oxygen, with the proviso that (1) sulfur must be linked to at least one carbon atom in all such radicals and is linked only to atoms of the group consisting of carbon and sulfur, and (2) such radicals must be free from any group having 8 or more uninterrupted carbon atoms; and n and n are whole numbers with the proviso that 11. plus 1:. equals a sum varying from 15 to 80; and R is the radical of a dicarboxy acid COOH in which R is a divalent radical composed exclusively of carbon, hydrogen and sulfur, with the proviso that (a) sulfur must be linked to at least one carbon atom, and (b) such radical must be free from any group having 8 or more uninterrupted carbon atoms; and n and n are whole numbers with the proviso that 11. plus n equals a sum varying from 15 to 80; and R is the radical of a dicarboxy acid COOH COOH said dicarboxy acid having not more than 8 carbon atoms; with the further proviso that the parent dihydroxy compound prior to esterification be water-insoluble and kerosene-soluble.

5. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsifier including hydrophile synthetic products; said hydrophile synthetic products being characterized by the following formula and n and n are whole numbers withthe proviso that 12 plus n equals a sum varying from 15 to and R is the radical of a dicarboxy acid /GO0H R COOH said dicarboxy acid having not more than 8 carbon atoms; with the further proviso that the parent dihydroxy compound prior to esterifi REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Blair Aug. 7, 1951 Number 

1. A PROCESS FOR BREAKING PETROLEUM EMULSIONS OF THE WATER-IN-ROLL TYPE CHARACTERIZED BY SUBJECTING THE EMULSION TO THE ACTION OF A DEMULSIFIER INCLUDING HYDROPHILE SYNTHETIC PRODUCTS; SAID HYDROPHILE SYNTHETIC PRODUCTS BEING CHARACTERIZED BY THE FOLLOWING FORMULA: 